A large number of systems are known for locating and tracking mobile objects, such as ship, planes, vehicles, etc. Some recent examples include, U.S. Pat. No. 6,298,306, “Vehicle Locating System Utilizing Global Positioning,” issued to Suarez, et al. on Oct. 2, 2001, and U.S. Pat. No. 6,348,889, “Radar Apparatus,” issued to Ashihara, et al. on Feb. 19, 2002. In general, the prior art systems focus on physical layer aspects of detecting signals in the presence of noise. Current transceiver designs can effectively locate and track objects with an accuracy of several meters.
Advanced systems can reliably locate and track multiple objects with a high degree of precision, see U.S. Pat. No. 6,349,259, “Navigation Apparatus and Information Generating Apparatus,” issued to Sato on Feb. 19, 2002, U.S. Pat. No. 6,275,773, “GPS Vehicle Collision Avoidance Warning and Control System and Method,” issued to Lemelson, et al. on Aug. 14, 2001, and U.S. Pat. No. 6,133,867, “Integrated Air Traffic Management and Collision Avoidance System,” issued to Eberwine, et al. on Oct. 17, 2000. All of these systems are capable of locating and tracking at least one mobile object relative to a stationary object or a mobile object.
The above systems could be adapted for general use and consumer applications. However, prior art systems are not designed for providing personalized services to different users. In recent years, a greater emphasis on personalized services has emerged. Personalized services are customized to the location and preferences of mobile users.
U.S. Pat. No. 5,642,303, “Time and Location Based Computing,” issued to Small et al. on Jun. 24, 1997, describes a system that allows users to define their own personal infrastructure by placing beacons at key locations to provide intelligent location awareness. As an advantage, that system does not require a network or server infrastructure, and unlike GPS systems, that system has no line-of-sight restrictions so that it can be used indoors. With beacons placed at various locations, such as in a home or in an office, that system provides users with information based on their locations and preferences.
However, because that system does not make use of existing networks, it is of limited use outside of the users “home area.” Location aware services (LAS) would be of greater value if they could be used at locations that are unfamiliar to users.
U.S. Pat. No. 6,331,817, “Object Tracking Apparatus and Method,” issued to Goldberg on Dec. 18, 2001, describes a tracking system that includes a tracked object interrogator, a location interrogator and an alarm. The object of that system is to report when an object is not near an expected location, object or person. The system accomplishes this task by tracking an object or a group of objects that may be needed by the user at different times of the day or for different tasks. The tracked object interrogator produces an object identifier, while the location interrogator produces an output corresponding to its proximity relative to a location transducer. An alarm is signaled based on predetermined combinations of the object identifier and location output.
Location services should be carefully distinguished from location aware services. Location services, such as GPS, merely provide positional information, while LAS involve the delivery of customized services to objects and users according to location information.
The concept that a networked system can include a database that keeps track of location information is not new. As shown in FIG. 1, Catovic et al., in “Geolocation Updating Scheme For Location Aware Services in Wireless Networks,” Proc. MobiCom'01, 2001, describe a mobile switching center (MSC) 100 for locating and tracking mobile terminal devices 101, e.g., cellular telephones, portable computers, personal digital assistants, and the like. The location information is then stored in a “geolocation component” 102. This structure can be used for cellular telephone networks.
Maass, in “Location Aware Mobile Applications Based on Directory Services,” Proc. MobiCom'97, 1997, describes a more complete system. A so-called location information server provides location information. Then, customized services are delivered according to user profiles and the location information.
In the context of personalized services, a calendar can be viewed as a rich source of personal information. For one, it can provide information regarding the location of a particular person at a given time. Additionally, a calendar can be used to help schedule events, such as meetings and or appointments. In order to foster an open exchange of calendaring and schedule information across the Internet, a common format for group scheduling and personal information management has been defined, see Dawson and Stenerson, “Internet Calendaring and Scheduling Core Object Specification,” RFC2445, November 1998. In that specification, methods that provide support for calendaring and scheduling operations are defined, such as requesting, replying to, modifying and canceling, to-dos and journal entries. The specification also defines a formal grammar for a wide range of descriptive elements used in calendaring and scheduling systems.
As part of the descriptive elements in RFC2445, a method for identifying users is specified, as well as various ways to represent time, such as the date, time of day, duration of an event, and relative time. There are two primary descriptions of location. The first is the GEO component, which is capable of specifying very exact locations, i.e., in terms of latitude and longitude. The values of this component can be determined by a GPS system. The second component is called LOCATION. This component is entered by the user as free text. It is well known that free text is not interoperable in that a description parser cannot easily interpret the semantics of the text. Free text is only useful in applications where the text can be rendered.
In general, prior art location aware services only consider the location and preferences of the user when delivering services. Prior art location aware systems do not consider the total environment in which the service is being delivered. Therefore there is a need to provide more advanced location aware services that effectively customize, adapt and deliver multimedia services considering not only the environment surrounding the user, but also the terminal device, the service provider, and the means that connect the device to the service provider.